Automatic slope and gain (ASG) detector technique including a pilot signal
US6587012B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 2, 2000 |
| Grant date | Jul 1, 2003 |
| Priority date | — |
| Expiry date | Oct 2, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/102
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus (7) for switching from a first pilot signal and a second pilot signal on a system transporting a plurality of signals. A tuner (30) receives the signals and provides an output signal to a loop compensation circuit (26). The tuner includes a bandpass filter (22) for removing signals other than the selected pilot signal from the output of the tuner. The output of the bandpass filter is provided to a detector circuit (24, 25). The output of the detector is compared with a reference signal (28) by the loop compensation circuit (28). A microcontroller (39) sends a tuning command to the tuner which causes the tuner to switch from tuning to the first pilot signal to tuning to the second pilot signal and also sends a new reference voltage to the loop compensation circuit. Thus, if the input signal changes from analog to digital modulation on the pilot channel, the set-point, or target level of the reference signal, will automatically change to provide the correct value for operation of the circuit. The microcontroller may change the selected pilot signal based upon a command in the input signal or upon an operator command, such as by setting a switch (not shown).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.